1. Field of the Invention
The present invention relates to a "karaoke" system supplying signals of musical performance and video images relevant to the musical performance to a plurality of terminals from a center system which constitutes a part of a CATV system, a CCTV system, etc. More particularly, the present invention is concerned with a karaoke system using digital musical performance information conforming to a MIDI (Musical Instrument Digital Interface) standard or the like.
2. Description of the Prior Art
Conventionally, a CCTV (Closed Circuit Television) karaoke system is known in which karaoke is provided by means of a CCTV system utilized in limited facilities, such as a building and identical grounds. The CCTV karaoke system is incorporated with services to individual rooms in a hotel or the like, or provides a karaoke service in which a building has a large number of rooms to each of which karaoke is provided.
FIG. 1 shows the structure of is a conventional CCTV karaoke system. As shown in FIG. 1, the conventional CCTV karaoke system includes a CCTV center system 100 and terminal systems R1, R2, . . . respectively provided in rooms in which music performance is carried out. The CCTV center system 100 and the terminal systems R1, R2, . . . are connected to each other by means of cables, and two-way communications take place between these systems. For example, requests are transmitted from the terminal systems R1, R2, . . . to the CCTV center system 100, which transmits signals of music pieces to be played and relevant video images to the terminal systems R1, R2, . . .
Each of the terminal systems R1, R2, . . . is made up of a CCTV converter 130, a mixing amplifier 131, a speaker 132, a microphone 133, a television set 134 and a remote controller 135. The CCTV converter 130 transfers information concerning a requested music piece set by an operation on the remote controller 135 to the CCTV center system 100. Further, the CCTV converter 130 receives a television signal transmitted via the cable, and separates the received television signal into a video signal and an audio (stereo) signal. The video signal is sent to the television set 134, and the audio signal is sent to the speaker 132 via the mixing amplifier 131. In this manner, the requested music pieces are played and the relevant video images are displayed.
The CCTV center system 100 is made up of a terminal controller 101, a commander 102, an RF mixer 103, a laser-vision disk (LD) automatic changer/player units, 111, 112, . . . , and television modulators 121, 122, 123, 124, . . . The terminal controller 101 performs the management and control of the center system 100, as well as control of communications with the terminal systems R1, R2, . . . The terminal controller 101 receives requests for musical performance from the terminal systems R1, R2, . . . , and sends related instructions to the commander 102. The commander 102 controls the LD automatic changer/player units 111,112, . . . , (each having two players and outputs), so that signals of the performance of the requested music pieces and the related video images are reproduced from laser-vision disks. Then, the video signals and the musical performance signals are converted into RF signals by the television modulators 121,122, . . . , and are transmitted, via the RF mixer 103, to the terminal systems which have issued the requests. In the above manner, the requested music pieces are played and the related video images are displayed in each of the terminal systems.
The CCTV center system as described above uses the LD automatic changer/player units, each of which accommodates laser-vision disks equal in number to music pieces, each of the disks storing the audio and video signals of a music piece. In response to a request for musical performance, an idle LD automatic changer/player unit is selected under the control of the terminal controller 101, and one of the laser-vision disks corresponding to the requested music is selected and played. The video and audio signals reproduced from the selected laser-vision disk are transmitted to the terminal system which has issued the above request.
However, the above-mentioned conventional CCTV center system has the following disadvantage. In order to process a number of requests, the CCTV center system must be equipped with a plurality of LD automatic changer/player units at a certain ratio thereof to the rooms to which the karaoke services are provided. Hence, it is necessary to increase the number of LD automatic changer/player units to be provided in proportion to the number of rooms, so that the equipment investment is increased and the space for placing the LD automatic changer/player units is also increased in proportion to the number of changer/player units.
Further, the LD automatic changer/player units are allowed to accommodate a limited number of disks. Nowadays, an increased number of new disks is released. The services of newly released disks can be provided by extending the LD automatic changers of the units. However, in this case, it is necessary to extend the automatic changers in all the LD automatic changer/player units of the system. This is troublesome in terms of the cost and the space.